U.S. patent number 5,017,904 [Application Number 07/509,124] was granted by the patent office on 1991-05-21 for braking indicator system.
This patent grant is currently assigned to General Motors Corporation. Invention is credited to Alan L. Browne, Yuen-Kwok Chin.
United States Patent |
5,017,904 |
Browne , et al. |
May 21, 1991 |
Braking indicator system
Abstract
A vehicle braking indicator system that provides a continuous
lighting of the vehicle stop light under normal braking conditions
but causes the stop light to be intermittently lighted at a
relatively high frequency when the anti-lock braking system of the
vehicle is activated.
Inventors: |
Browne; Alan L. (Grosse Pointe,
MI), Chin; Yuen-Kwok (Grosse Pointe, MI) |
Assignee: |
General Motors Corporation
(Detroit, MI)
|
Family
ID: |
24025370 |
Appl.
No.: |
07/509,124 |
Filed: |
April 16, 1990 |
Current U.S.
Class: |
340/479;
340/467 |
Current CPC
Class: |
B60Q
1/448 (20130101) |
Current International
Class: |
B60Q
1/44 (20060101); B60Q 001/46 () |
Field of
Search: |
;340/453,463,467,479,436
;188/1.11 ;303/103 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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|
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|
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3400806 |
|
Jul 1985 |
|
DE |
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3804094 |
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Aug 1989 |
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DE |
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Primary Examiner: Orsino; Joseph A.
Assistant Examiner: Tumm; B. R.
Attorney, Agent or Firm: Biskup; Edward J.
Claims
The embodiments of the invention in which an exclusive property or
privilege is claimed are defined as follows:
1. A braking indicator system for a vehicle having an anti-lock
braking system including an anti-lock electronic control unit, a
brake pedal, a stop light lamp mounted on the rear end of said
vehicle, an electric circuit including a normally open switch and a
normally-closed switch providing for continuous energization of
said stop light upon depression of said brake pedal, and means
including a square wave generator electrically connected between
said anti-lock electronic control unit and said normally closed
switch for causing the normally closed switch to provide a flashing
signal upon activation of said anti-lock braking system.
2. A braking indicator system for a vehicle having an anti-lock
braking system, a brake pedal, a stop light lamp mounted on the
rear end of said vehicle, an electric circuit including a normally
open switch and a normally-closed switch providing continuous
energization of said stop light lamp upon depression of said brake
pedal under normal braking conditions, means electrically connected
to said normally closed switch for causing said stop light lamp to
provide a flashing signal upon activation of said anti-lock braking
system, said means including an anti-lock electronic unit providing
an output signal from a discrete output port when the anti-lock
brake system limits wheel slip of said vehicle, a driver module for
receiving said output signal from said electronic control unit and
for generating a driving signal, and a square wave generator which
upon receiving said driver causes said normally closed switch to
open and close at a predetermined high frequency so as to provide
said flashing signal of said stop light lamp.
3. A braking indicator system for a vehicle having an anti-lock
braking system, a brake pedal and a stop light lamp mounted on the
rear end of said vehicle and a sound generating device located in
the passenger compartment of the vehicle, an electric circuit
including a normally closed switch means providing continuous
energization of said stop light lamp upon depression of said brake
pedal under normal braking conditions and also a normally open
switch means for causing said generating device to provide an
audible signal to the vehicle driver, means electrically connected
to said normally closed switch means and said normally open switch
means for causing said stop light lamp to provide a flashing signal
upon activation of said anti-lock braking system and simultaneously
provide said audible signal to the driver, said means including an
anti-lock electronic control unit providing an output signal from a
discrete output port when the anti-lock brake system limits wheel
slip of said vehicle, a driver module for receiving said output
signal from said electronic control unit for generating a driving
signal, and a square wave generator interfacing with said normally
open switch means and said normally closed switch means so that
upon receiving said driver signal, both of said switch means open
and close at a predetermined frequency so as to provide said
flashing signal of said stop light lamp and said audible signal to
said driver.
Description
This invention concerns braking systems for motor vehicles and more
particularly concerns a braking indicator system which causes a
stop light to provide a flashing signal to a following vehicle
whenever the anti-lock braking system of the vehicle is
activated.
BACKGROUND
In order to prevent wheel lockup when excessive brake pressure is
applied to the wheel brakes by the vehicle operator and to maintain
a stable braking condition, it is becoming quite common for present
day vehicles to have an electrically controlled anti-lock braking
system. In general, these systems respond to parameters derived
from wheel speed, such as wheel acceleration or deceleration and
wheel slip, to control or limit the pressure applied to the wheel
brakes. Generally, these systems provide for a decrease in brake
pressure when an incipient wheel lockup condition is detected to
allow the vehicle to recover from the incipient lockup condition
followed by a reapplication of braking pressure to the wheel. This
cycle is rapidly repeated until the vehicle stops or until the
operator applied braking pressure is reduced to a level below that
which produces an incipient wheel locking condition.
SUMMARY OF THE INVENTION
The present invention intends to combine the anti-lock braking
system of the type described above with the stop light electrical
circuit in a manner so as to cause the stop light to flash at a
predetermined high rate when the brake pedal is depressed but only
when the anti-lock brake system is activated. In one form of the
invention, this is realized by providing a braking indicator system
which includes an electric circuit having a normally closed switch
which allows continuous energization of the stop lamp upon
depression of the brake pedal if the anti-lock braking system is
not activated. However, upon depression of the brake pedal under
conditions which cause the activation of the anti-lock braking
system, drive means serve to rapidly open and close the normally
closed switch causing the stop light to provide a flashing signal
so as to indicate to the following vehicle that the anti-lock
braking system is controlling the braking of the vehicle. In the
preferred form, the drive means for providing this result includes
a drive module and a square wave generator connected in series
between the electronic control unit of the anti-lock braking system
and the normally closed switch. Thus, when the anti-lock braking
system is activated due to excessive brake pressure being applied
to the wheel brakes, the electronic control unit will provide an
output from a discrete output port which is received by the driver
module. The driver module, in turn, generates a drive signal which
is received by the square wave generator and causes the latter to
open and close the relay at a predetermined high rate so that the
stop light intermittently is energized and deenergized to convey
the message to the following vehicle that the braking vehicle's
anti-lock brake system has been activated. In a modified form of
the invention, the braking indicator system not only causes the
vehicle stop light lamp to flash when the anti-lock braking system
is activated but also serves to inform the driver visually and
audibly of the activation of the anti-lock braking system. In the
modified system, the square wave generator serves to drive a
normally open switch to pulse the anti-lock braking system telltale
light on the instrument panel of the vehicle. In addition to
pulsing the anti-lock braking system telltale light, the square
wave generator interfaces with chimes to indicate to the driver of
the activation of the anti-lock braking system.
The objects of the present invention are to provide a new and
improved braking indicator system for a motor vehicle which causes
the stop light to flash at a predetermined high frequency only when
the anti-lock braking system of the vehicle is activated; to
provide a new and improved braking indicator system which includes
switch means in the stop light electric circuit that is
automatically opened and closed at a predetermined frequency so as
to cause the stop light to flash whenever the vehicle anti-lock
braking system is activated; to provide a new and improved braking
indicator system for a vehicle that provides a visual signal to the
following vehicle and an audible and visual signal to the driver of
the leading vehicle that its anti-lock braking system has been
activated as a result of depression of the brake pedal; and to
provide a new and improved vehicle braking indicator system that
provides a continuous energization of the vehicle stop light under
normal braking conditions, but which causes the stop light to be
intermittently energized at a relatively high frequency when the
anti-lock braking system of the vehicle is activated.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the present invention will be more
apparent from the following detailed description when taken with
the drawings in which
FIG. 1 is a schematic diagram of a braking indicator system for a
motor vehicle made in accordance with the present invention,
and
FIG. 2 is a modified form of the braking indicator system shown in
FIG. 1.
DETAILED DESCRIPTION
Referring now to the drawings and more particularly FIG. 1 thereof,
a motor vehicle brake indicator system is shown which includes an
electrical stop light system combined with an electronic control
unit (ECU) 10 of an anti-lock braking system (ABS) which, in turn,
is coupled to the electrical circuit portion 12 of the stop light
system through a driver module 14 and a square wave generator
16.
More specifically, the electrical circuit portion 12 of the stop
light system includes a source of electrical power such as a
battery 18, a motor vehicle rear stop light lamp 20, and a normally
open brake switch 22 which is adapted to be closed by the vehicle
driver upon depression of a conventional brake pedal 24 which is
suitably supported for pivotal movement by a pivotal connection 26.
In addition, switch means 28 in the form of a relay is located in
series with the brake switch 22 and the lamp 20 and includes the
usual relay coil which, when energized, opens normally-closed
contacts 32. Thus, during normal braking conditons when the
anti-lock braking system is not activated, depression of the brake
pedal 24 by the driver causes continuous energization of the lamp
which is then visible to the following vehicle.
When braking conditions are such that wheel lockup of one or more
of the vehicle wheels may occur, the anti-lock braking system will
be activated so as to maintain a stable braking condition. When
this occurs, an output signal from a discrete output port of the
anti-lock braking system ECU 10 is coupled to the drive module 14
which provides a drive signal to the square wave generator 16. The
output from the drive module 14 is typically a discrete voltage
signal for enabling the square wave generator 16. As a result, the
square wave generator 16 delivers a square wave with a
predetermined frequency such as, for example, between 3 to 5 Hz to
the relay coil 30 causing the latter to be intermittently energized
and deenergized so as to open and close the contacts 32. This, in
turn, causes a flashing of the stop light lamp 20 to alert the
following driver that the anti-lock braking system of the vehicle
has been activated.
A modified form of the invention is shown in FIG. 2 in which the
components corresponding to those shown in FIG. 1 are identified by
the same reference numerals but primed. In this case, the braking
indicator system not only causes the stop light 20' lamp to flash
when the anti-lock braking system is activated, but also serves to
inform the driver visually and audibly of the activation of the
anti-lock braking system. Thus, as seen in FIG. 2, the square wave
generator 16' can serve to drive a second relay 34 to pulse the ABS
telltale light 36 on the instrument panel of the vehicle. In this
instance, it will be noted that the relay 34 includes a relay coil
38 and normally-open contacts 40 so that the lamp 36 is not
energized until the ABS is activated. In addition to pulsing the
ABS telltale light 36, the square wave generator 16' interfaces
with chimes 42 (such as currently used to indicate on GM vehicles
that the headlamps are still lit after the ignition key is turned
to the "off" position) and thereby informs the driver of the
activation of the ABS. As would be understood to those skilled in
the art, this invention can similarly be implemented for traction
control systems operating during vehicle acceleration.
Various changes and modifications can be made in the system
disclosed herein without departing from the spirit of the
invention. Such changes and modifications are contemplated by the
inventors and they do not wish to be limited except by the scope of
the appended claims.
* * * * *